The Future of Agricultural Land Suitability in Hawaiʻi: GIS Analysis of Coffee & Taro

Abstract

Climate change is a concerning phenomenon, especially when it comes to the diverse impacts it has on agriculture and crop production. This study employed geographic information system (GIS)-based suitability modeling to assess the impact of future temperature and rainfall conditions on the suitability of growing coffee, and dryland taro. The crops were selected based on economic viability, cultural significance, and historical growth success in Hawaiʻi. The optimum crop growth conditions (i.e., climate, soil, and topographic conditions) were determined by integrating industry experts’ and farmers' insights and knowledge into the data collection process. These growth conditions were then spatially extrapolated to the main Hawaiian Islands through GIS. Future climate data were obtained from WorldClim and downscaled to Hawaiʻi, including the 12 most recent global climate models available (Coupled Model Intercomparison Project Phase 6, CMIP6) across two shared socioeconomic pathways (SSP 245 and 585) spanning the years 2021-2080 in 20-year intervals. SSP 245 and 585 are two different climate futures based on economic and social development and the related greenhouse gas (GHG) emissions. The 12 models and two pathways were used to account for the varying results of future climate models. Results for coffee suggest positive trends for the crop to remain viable on current farmlands over the next 60 years with gradual climate change. Land suitability analysis on dryland taro revealed a steady increase across agricultural land, with the potential to become a staple crop for local food production. Overall, farming in Hawaiʻi must continue to ramp up despite climate change to meet local demand and reduce dependence on import goods.